Interracial partnering across the USA has reached new levels, according to 2010 Census data released Wednesday that reflect sharp increases in the percentages of people of different races who are married or live together.

Among opposite-sex married couples, one in 10 (5.4 million couples) are interracial, a 28% jump since 2000. In 2010, 18% of heterosexual unmarried couples were of different races (1.2 million couples) and 21% of same-sex couples (133,477 couples) were mixed.

The data show “we’re becoming much more of an integrated, multiracial society,” says demographer William Frey of the Brookings Institution.

• STORY: Interracial marriage: More accepted, still growing

Says sociologist Dan Lichter of Cornell University in Ithaca, N.Y., “This is a movement toward a post-racial society, but most social scientists would agree we’re a long way from a colorblind or post-racial society.

“Race is still a category that separates and divides us,” but “this might be evidence that some of the historical boundaries that separate the races are breaking down,” Lichter says.

Christelyn Karazin, 38, of Temecula, Calif., on Friday celebrates the 10th anniversary of her marriage to Michael Karazin, 39. She is black; he is white.

She says the Internet has allowed more people of different races to interact. She and her husband, who met online, “would never have met” otherwise. “He’s from Westport, Conn. His father is a judge. My parents are from the country in Texas. My mom picked cotton.”

Other trends in households from 2000 to 2010:

•Non-family households rose 16% (34 million to 39 million).

•Households with just one person increased from 25.8% to 26.7%; among cities with 100,000 or more people, Atlanta and Washington had the highest percentage of one-person households, both 44%.

•Unmarried-partner households increased from 5.5 million to 7.7 million.

•Households with three or more generations rose from 3.9 million to 5.1 million; 9% of households in Hawaii were multigenerational, the highest percentage of any state.